In a conventional map information processor, image data showing a landmark to be displayed on a map such as a facility is managed in the outside of meshes independently from data managed on a mesh-by-mesh basis (for example, refer to patent reference 1).
It takes much time to perform a map image generating process when referring to required image data every time when generating a map image from such image data managed in the outside of meshes, and the performance of the map information processor therefore degrades. To solve this problem, the conventional map information processor shortens the time required to perform the map image generating process by reading image data managed in the outside of meshes into a RAM in advance.
[Patent reference 1] JP,2005-214783,A
However, in a case of handling image data having a data amount exceeding the capacity of the RAM disposed in the map information processor, a situation in which the map information processor cannot read all the image data into the RAM occurs. Therefore, there is a demand to implement map image generation in a short time also in such a situation.
The present invention is made in order to meet the above-mentioned request, and it is therefore an object of the present invention to provide a map information processor that can shorten the time required to perform a map image generating process.